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    Ezequiel52125
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Passive PoE Switch + Response Gateway

Can a passive Poe switch work with a Response Gateway? I have a couple of Response Gateways that work perfectly with a Cisco switch but when I connect them to a generic passive switch in a another venue they don't turn on. 

The generic switch label says PoE output pin: 4,5(+) / 7,8 (-). Do I need a different cable?

Do you think I can still use this switch or it is easier to use a power supply to feed to gateway?

Thanks.

E.-

  • Hi,

    I should start off with a warning regarding so called "passive PoE" injectors. They can cause damage to equipment; and with some implementations I've seen, potentially cause damage to property and persons.

    There are two basic ways of transmitting power over ethernet installations. "Passive PoE" aka "CCTV PoE", and the official IEEE (802.3af/802.3at/802.3bt) way.

    ()The passive way simply sends power down "unused" pins of the cat5 (or equivalent) ethernet cable. This power is unrequested, unmanaged, and occasionally unfused. I've even seen unseparated from mains potential.

    Suffice to say it should be avoided.

    () The official IEEE way incorporates a number of revisions of the standard (802.3af/802.3at/802.3bt) each being able to supply more current than the last, but remaining basically backwards compatible.

    The standards allow a powered device (PD) to request if needed power from a power sourcing equipment (PSE).

    A PSE can be a switch or a midspan device.

    Power can be (depending on PSE implementation and PD requirements) sent via unused pins or merged in a similar style to the way phantom power works with balanced microphones.

    The PD requests the current required to power it's self and the PSE supplies this in a safe, regulated, and controlled manor.

    A PSE does not supply power to a device that does not request it.

    All ETC (and indeed many other industry equipment) that operate from PoE will only respond to the official IEEE method of over ethernet power.

    Regards,

    Marcus

  • in reply to marcusbirkin
    Hi Marcus,

    Thank for your answer. Got it. Response gateways are not passive PoE PD compliant. However in the meantime until I replace the switch, can I use the gateway with a power supply? Do you suggest to make a special ethernet cable and eliminate the "unused" pins where the passive switch sends power down?
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